Pyraline document-holding envelope



March 15 1927. 1,620,962 C. J. GUTBERLET PYRALINE DOCUMENT HOLDING ENVELOPE Filed Dec. 31, 1923 .Patented. Mar. .15, 1927.

UNITED STATES PATENT OFFICE.

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. PYBAIJNE DOCUMENT-HOLDING ENVELOPE.

Applicationflled December 31, 1928. Serial No. 683,883.

The pyraline document holding enveldpe, has the two walls formed from'one piece of sheet pyraline folded crosswise at the bottom of the envelope. One of these two side walls has retaining flaps that are folded over the outside of the other side wall, and yielding hold the latter near its edges and leave it free to slide sidewise between them and tached to. ,The inside edges of the .the inside of the side wall that they are at 3.

ps bear against the outside of the wall of the envelope which they hold. Folding the envelope from a single sheet withthe two side in 1y resilient material, this construction W1 result in a greatly enlarged capacity and in the contents of the envelope being held firmly between the side walls whether much or little is contained in the envelope.

Fig. 1 is a side elevation of the document holding envelope. Fig. 2 is an edge elevation thereof. Figs. 3 and 4 are sections on lines 3 and 4 respectively of Fig. 1. Fig.

I 5 a section on line 5 -5 of Fig. 1. Fi s.--6,

1 back and become flat repeatedl ,7 and 8 are illustrations of' a step 0 the process. Figs 6 shows it with "a side elevation of the envelope; Fi 7 with a section on line 3-3 of Fig. 1 0% same, and Fig. 8 a view of the envelope looked at from the top.

Pyraliri'e is a transparent stiflish material; when cold it is highly resilient, and not pliable. .A sheet of it, if bent, will spring and with considerable force and resists s rongly being permanently bent, although it yields readily and bends temporarily, but'tending always to spring backwards and to exert a pressure against the deforming material.

1' and 4 are the two side walls of the pyraline document'holding envelope. One of these walls has the fiaps,2, 2, that fold over a portion near each of the edges 0f the wall 4. The edge, 5, 0t theseflaps, 2, 2, which lies towards the middle line. ofthe envelope (see particularly Fig. 5) lies close to the outer face of the wall 4, and the curve being formed of a single sheet folded at the of the fold, 6, has diameter large enough toleave quite a space between the flaps, 2, 2,'

' and the wall 1, near the fold. This enables the wall, 4, to be substantially as wide as the wall, 1, without any danger that its edges will stick in the pocket between the flap, 2, 2, and wall, 1. The fold, 7, between,

the walls, 1 and 4'extends the entire width of the" envelope, and positions the wall, 4, exactly over the wall, 1. The stiffness of the pyraline walls, 1 and 4, makes this position positive, and their resiliency brings them backto its original fiat shape. The clamping efl'ect of the flaps, 2, 2, upon the wall, 4, is exerted at a point at or near the inner edges of the flaps. The effect of inserting any documents into the envelope is to make the edges of the side wall, 4, slide away from the bottom of the pockets formed between the flap, 2, 2, and the wall (away from the folds, 6). These movements, on account of .the length of the ,fold, 7, and the stifl'ness of the pyraline walls, will be equal, and the inner edges of the flaps, 2, 2, by lying close against the wall, 1 will hold the edge of the wall 4 against the wall, 1,- until the edges of the wall, 4, are withdrawn from beneath the flaps, ,2, 2'. This gives great holding capacity to the envelope and the resiliency of the-two sheets, 1 and 4c'lamped together, as above described; will hold the documents, whether a few or a large numher, very firmly, so that they will not slip out even if the envelopeshould be reversedor fall a distance.

The folds, 6, are made in a manner that produces the fullness above described at the bottom of the pocket between the flaps, 2,.2,

' and the wall, 1. 20, 20, is a pair of rollers turned by a handle, 21. Each roller is pro-"- vided with a rubber blanket, 22. The pyraline is softened by heating and passed through the rollers, 20, 20. The folds, 6, being started the rollers will press down the 'inner edges of the flaps, 2, 2', more than the parts of them near the folds, 6. This is because the fold will offer-a greater resist- Q ance to the pressure and will sink more deeply into the rubber blanket. This will produce the fullness atthe bottom of the pockets between the flaps, 2, 2,and the wall, 1, and the close clamping pressure of the inner part of the flaps, 2, 2, on the inside of wall, 1.

I claim- 1. A document pyraline, the two sidewalls of the envelope bottom of the envelope and one of the side walls being provided with flaps folding over holding envelopeof sheetforming pockets between them and-this wall, llnattached to the wall of the envelope inin which the outer edges of the other wall sorted in the pockets formed by these flaps.- l0 fit and in whichthey slide freely, the said 2. The device, as described inelaim 1,w1th flaps holding their position entirely by the this element additional :the pockets being 5 resiliency of the pyraline fabric, and their Wlde at the d between the flap and the turned over portions being free from the [Wall to which it is attached and contracted r wall of the envelope to which they are at at the inner edges of the flaps. V tached, and being entirely free from and CHAS. GUTBERLET. 

